On Wed, Oct 08, 2025 at 04:39:23PM +0200, Roger Pau Monne wrote: > I've had the luck to come across a PCI card that exposes a MSI-X capability > where the BIR of the vector and PBA tables points at a BAR that has 0 size. > > This doesn't play nice with the code in vpci_make_msix_hole(), as it would > still use the address of such empty BAR (0) and attempt to carve a hole in > the p2m. This leads to errors like the one below being reported by Xen: > > d0v0 0000:22:00.0: existing mapping (mfn: 181c4300 type: 0) at 0 clobbers > MSIX MMIO area > > And the device left unable to enable memory decoding due to the failure > reported by vpci_make_msix_hole(). > > Introduce checking in init_msix() to ensure the BARs containing the MSI-X > tables are usable. This requires checking that the BIR points to a > non-empty BAR, and the offset and size of the MSI-X tables can fit in the > target BAR. > > This fixes booting PVH dom0 on Supermicro AS -2126HS-TN severs with AMD > EPYC 9965 processors. The broken device is: > > 22:00.0 SATA controller: Advanced Micro Devices, Inc. [AMD] FCH SATA > Controller [AHCI mode] (rev 93) > > There are multiple of those integrated controllers in the system, all > broken in the same way. > > Signed-off-by: Roger Pau Monné <[email protected]> > Released-Acked-By: Oleksii Kurochko<[email protected]> > --- > Cc: Stewart Hildebrand <[email protected]> > Cc: Oleksii Kurochko <[email protected]> > --- > Changes since v1: > - Introduce a DEVICE BUG prefix. > - Remove extra newline. > - Fix typo in commit message. > --- > xen/drivers/vpci/msix.c | 50 ++++++++++++++++++++++++++++++++++++----- > xen/include/xen/lib.h | 3 +++ > 2 files changed, 48 insertions(+), 5 deletions(-) > > diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c > index 54a5070733aa..4ddcefbcb274 100644 > --- a/xen/drivers/vpci/msix.c > +++ b/xen/drivers/vpci/msix.c > @@ -675,6 +675,51 @@ static int cf_check init_msix(struct pci_dev *pdev) > if ( !msix ) > return -ENOMEM; > > + msix->tables[VPCI_MSIX_TABLE] = > + pci_conf_read32(pdev->sbdf, msix_table_offset_reg(msix_offset)); > + msix->tables[VPCI_MSIX_PBA] = > + pci_conf_read32(pdev->sbdf, msix_pba_offset_reg(msix_offset)); > + > + /* Check that the provided BAR is valid. */
I had the following local change that I forgot to update the patch with before sending: /* Check that the referenced BAR(s) regions are valid. */ I think this is a better wording. Thanks, Roger.
